docs: def schnorr_generate_nonce_pair(self, msg, raw=False,
                                      digest=hashlib.sha256):
          """
          Generate a nonce pair deterministically for use with
          schnorr_partial_sign.
          """
          if not HAS_SCHNORR:
              raise Exception("secp256k1_schnorr not enabled")
  
          msg32 = _hash32(msg, raw, digest)
          pubnonce = ffi.new('secp256k1_pubkey *')
          privnonce = ffi.new('char [32]')
  
          valid = lib.secp256k1_schnorr_generate_nonce_pair(
              self.ctx, pubnonce, privnonce, msg32, self.private_key,
              ffi.NULL, ffi.NULL)
          assert valid == 1
  
          return pubnonce, privnonce